The road ahead for ultrawide bandgap solar-blind UV photodetectors

Abstract

This Perspective seeks to understand and assess why ultrawide bandgap (UWBG) semiconductor-based deep-UV photodetectors have not yet found any noticeable presence in real-world applications despite riding on more than two decades of extensive materials and devices’ research. Keeping the discussion confined to photodetectors based on epitaxial AlGaN and Ga2O3, a broad assessment of the device performance in terms of its various parameters is done vis-à-vis the dependence on the material quality. We introduce a new comprehensive figure of merit (CFOM) to benchmark photodetectors by accounting for their three most critical performance parameters, i.e., gain, noise, and bandwidth. We infer from CFOM that purely from the point of view of device performance, AlGaN detectors do not have any serious shortcoming that is holding them back from entering the market. We try to identify the gaps that exist in the research landscape of AlGaN and Ga2O3 solar-blind photodetectors and also argue that merely improving the material/structural quality and device performance would not help in making this technology transition from the academic realm. Instead of providing a review, this Perspective asks the hard question on whether UWBG solar-blind detectors will ever find real-world applications in a noticeable way and whether these devices will be ever used in space-borne platforms for deep-space imaging, for instance.

Function of a Dual-Active-Layer Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistor with Ultraviolet-Induced Effects

“…Most importantly, the low-cost production of the UV sensor is a key to practical applications, which suggests that the production of the sensor material or the device fabrication should be easy. In addition, the self-amplifying circuit should also be as simple as possible or be included in the sensing properties. − …”

Efficient Acceptor Doping of Sputter-Deposited p-Type NixGa1–xO Rocksalt Alloy with Li

“…Gallium oxide (Ga 2 O 3 ), an ultrawide band gap material with a band gap value of 4.5–5 eV, has recently gained renewed interest as a potential material for high-power electronics , and solar-blind UV photodetectors. − The monoclinic β-Ga 2 O 3 is the most widely studied thermally stable phase with a theoretically predicted critical breakdown field strength of ∼8 MV/cm . Experimentally, β-Ga 2 O 3 MOSFETS and a dielectric heterojunction diode with breakdown field values of ∼3.8–5.7 MV/cm have been demonstrated. − In addition to the large band gap and thermal stability, relatively inexpensive bulk β-Ga 2 O 3 substrates are available, which further enable the epitaxial growth of high-quality β-Ga 2 O 3 thin films. ,− These unique characteristics of Ga 2 O 3 have made it emerge as a potential material for various high-power and deep UV devices, including power electronics, microwave and radio frequency devices, solar-blind photodetectors, and solar cells. ,, …”

15 MeV proton damage in NiO/β-Ga2O3vertical rectifiers

“…β-Ga 2 O 3 is attracting significant recent attention for power switching devices [1][2][3] and solar-blind UV photodetectors [4]. In particular, significant advancements have been achieved in the development of NiO/β-Ga 2 O 3 power rectifiers, surpassing the performance limitations observed in GaN structures, particularly in one-dimensional configurations [5][6][7][8].…”